JP2016196791A - Seabed cutting/banking system and method, and loading box body and work ship used therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give priority to reduction of seabed soil (dredged soil) to be carried out in maintenance of water depth of a sea route and a berth while securing the water depth that results from settlement of the seabed, the soil carried out being minimized and a volume thereof being reduced by hydration through compression (compaction) and settlement, without polluting the surrounding, and recycled after obtaining required strength.SOLUTION: A work ship 1 is used for compression and settlement of a seabed for maintaining a water depth, the work ship being provided with a tower-type loading box body 5 with draining and depressurizing functions. The loading box body 5 is embedded in the seabed at a water depth maintenance work section, and seabed soil is compressed to reduce a volume thereof by loading atmospheric pressure and water pressure. Then, a bottom surface of the loading box body 5 is closed at a prescribed strength, with the seabed soil filled therein. The loading box body is then transported underwater to a receiving section. The loading box body 5 is lowered to the seabed in the receiving section, and the seabed soil is drawn out for banking. The seabed soil remains being filled inside the loading box body 5.SELECTED DRAWING: Figure 4

Description

  TECHNICAL FIELD The present invention relates to cutting and transporting seabed soil in ship routes, anchorage deepening, and water depth maintenance, and embankment as reuse of seabed soil.

  In recent years, as the size of ships has increased, it has been required to deepen the waterways and anchorages. In addition, the channel and anchorage are always shallower due to the flowing sediment (inflowing sediment). Dredging is carried out regularly to secure the water depth, and a large amount of dredged soil has been generated. Dredged soil has been used for landfill disposal, tidal flats, and shallow land creation, but securing such disposal sites is becoming difficult year by year.

  The main methods are pump and grab. Pump dredging is a method of large-scale dredging, in which a ladder (suction pipe) is lowered to the seabed by a pump dredger, the cutter is rotated to crush the earth and sand, sucked with seawater with a large pump, and transported using a sand drain pipe. Grab dredging is a method for small and medium-sized dredgers, using grab dredgers to grab the earth and sand with a grab bucket and load them on an earth transport ship.

  Submarine soils are mostly soft soils with high water content, while dredged soils are very soft soils. Dredged soil is artificially made ultra-soft soil. Pump dredging is the soil that sucks the seabed soil together with seawater with a large pump. It is said that the water content when pump clay is thrown into the disposal site is about 2,000%. On the other hand, Grab Pass is the soil that has been put into a ship by excavation in the sea and reconstituted. It is said that the water content of the grab dredged by the reclaimer ship is about 200% for viscous soil and about 2 to 3 times the liquid limit.

  The water content of alluvial clay in Japan is 30 to 150%, and the liquid limit is about 50 to 130%.

  The disposal of dredged soil is easiest if it can be put into the ocean. However, offshore disposal is severely restricted from environmental efforts. As an international effort to protect the marine environment, there is the “London Convention” for the purpose of preventing marine pollution caused by the dumping of waste. To ensure this, the “Law Concerning the Prevention of Marine Pollution and Maritime Disasters” has been revised, and the “Technical Guidelines for the Disposal of Dredged Sediment into the Sea” is presented.

  Since it is difficult to secure a disposal site for dredged soil, recycling of dredged soil has been promoted in recent years. Dredged soil is very soft soil with high water content. This is especially true for clay soils. For this reason, it is used for artificial island landfill materials such as harbors and airports after dehydration and volume reduction at the plant or by improving the material with sufficient strength by mixing solidification material (cement, etc.).

  The priority for waste recycling measures is control, reuse, and recycling. Regardless of whether you are in need of landfill to the point where you have to use dredged soil, the recycling measures for dredged soil must be the same. The current dredged material recycling measures do not control the outbreak and are suddenly recycled. In addition, dehydration and volume reduction are carried out in the plant after removing the dredged soil, so it is not a suppression. The recycling of dredged soil is made by artificially creating ultra-soft soil, which is artificially recycled.

  Patent No. 4996883 (Japanese Patent Application No. 2006-166657)

Patent Document 1 is a method (hereinafter referred to as the construction method of Patent Document 1) in which viscous land is rapidly consolidated and subsidized regardless of whether the water depth is maintained or secured. The factors that promote consolidation settlement of cohesive ground are settlement amount and consolidation time. Subsidence amount of compaction load size, shortening of the compaction time is shortened drainage distance (H ² rule). A method of using atmospheric pressure for the consolidation load is a vacuum consolidation method, and when this is carried out on the seabed, water pressure is further applied. A vertical drain is placed on the seabed to shorten the consolidation time. The method of Patent Document 1 is an experiment that if a small repetitive load (only 6% of the consolidation static load) is added to the consolidation static load (atmospheric pressure + water pressure) to generate a wave of excess pore water pressure, it will greatly promote consolidation settlement. It showed in.

  The maintenance of the water depth by the construction method of Patent Document 1 is the consolidation settlement of the seabed ground, and no dredging is generated and it is completely suppressed. This method is limited to cohesive land, and is not suitable for intermediate and sandy ground between cohesive soil and sandy soil. However, it is clay that is troublesome to reclaim dredged soil. However, in the case of low plastic clay, the compressibility is small, so it is not suitable for large depth increase due to deepening of water depth. It is clear that this construction method is economically and environmentally superior because it is a complete suppression of dredged soil compared with the current dredged soil disposal method.

  JP-A-11-268683

  Patent Document 2 is a spud-type work ship. One is fixed to the hull, and the other is operated by a spud that has a reciprocating function in the hull axis direction, in addition to the stability of the hull, hull movement in the hull axis direction. Made possible. (Referred to as work boat of Patent Document 2)

  In securing and maintaining the water depth of the channel and anchorage, a construction method that can be applied to all submarine ground is preferred, with priority given to the suppression of unloading of the submarine soil. In addition, it is important to minimize the amount of unloading of the seabed soil, and to reduce the volume of dewatering without causing seawater pollution at the place of occurrence, and to increase the required strength and reuse it as a material. . For this purpose, the water depth can be secured without causing pollution, and the subsidence of the submarine ground that can reduce the volume and increase the strength of the discharged soil will be utilized to the maximum.

  The construction method of Patent Document 1 is limited to viscous land. This is because there is no means of transportation even if there is an outbreak of submarine soil to be carried out. Even if the submarine ground is compressed and subsidized, there is no point in drowning the subsidence by the conventional method.

  In the first place, the construction method of Patent Document 1 was developed mainly as a countermeasure for residual settlement of the ground of a port facility. It is often a large depth because the entire viscous soil layer of the ground is the target. Therefore, a prior process for placing a vertical drain on the seabed and laying a sand mat is required. In addition, the residual settlement is mostly secondary compaction and takes a long time. On the other hand, securing the water depth in the channel and anchorage has no relation to the residual settlement due to a decrease in consolidation increase load. It is how to subsidize the submarine ground in a short time. This is a contradiction, and somewhere needs to be negotiated.

  The pump dredging method is suitable for large-scale dredging, and the grab dredging is suitable for small- and medium-sized dredging. The desired construction method is a dredged soil control method that is efficient regardless of the size.

  The basic method for increasing the strength of soil is to increase the density. As a method for increasing the density of sand, dynamic compaction by vibration or impact is known. The same effect is observed even with repeated compression loads. On the other hand, as is known from the construction method of Patent Document 1, alluvial clay is promoted for consolidation when an appropriate repeated load is applied. As a result, the density of the saturated soil can be increased by using both a static load and a repeated load.

This is nothing but the dehydration and volume reduction at the place where the seabed soil (including the inflowing volume soil) is taken out and recycled as material. This can be applied to any soft soil such as clay soil, sandy soil, and intermediate soil, and can be applied to all submarine ground. Therefore, the problem as a construction method that can be applied to all submarine ground is that if there is an unloading seabed soil, this is minimized, how to keep the seabed soil raised to the required strength as it is, cut and transport, This results in the issue of re-use.
Here, compression of soil with low water permeability such as clay is accompanied by a time delay. This is called consolidation, but here it is used for all submarine grounds.

  The basic means for solving the problem is the mechanism and function of the work boat and the loading box. The mechanism of the loading box corresponds to the vacuum consolidation method so that the loading surface can be kept airtight. The rigid loading plate of the loading box is equipped with an automatic valve that controls the entry and exit of water, the entire bottom surface is provided with a thin space (drain layer) and two stages of rigid filters, and the outer peripheral wall is joined to the outer periphery of the bottom surface. It is a tower-type loading box with a loading tower that is high enough to reach the bottom of the sea. The loading tower is equipped with repeated loading devices. Further, the loading box has a lifting function, a pressure reducing function in an airtight state, a loading function of the seabed ground, an airtight releasing function, and a pressurizing function. Here, when the loading box is pushed into the seabed ground and depressurized in an airtight state, atmospheric pressure and water pressure are loaded on the loading box and transmitted to the seabed ground. When the airtight state is released and pressurized air is sent, the seabed soil in the packed state inside the loading box is pressurized. This function is used when extracting seabed soil. The mechanism / function of this loading box is basically the same as the pressure box of the construction method of Patent Document 1.

  The mechanism of the work ship is composed of multiple (2 to 4) floating ships that are floating bodies, their guide towers and tower-type loading boxes, and the multiple carriages are spaced at an interval where one side of the loading box fits. A plurality of guide towers are arranged and fixed to the connected three-dimensional frame. Each guide tower has a tower-type loading box. The basic shape of the horizontal cross-sectional area of the loading box is a square.

  An efficient construction method regardless of the size of the dredged soil control method. First, this problem is solved by the effect of the depth of the subsidence clay layer. That means deletes part of the work process. By limiting the ground subsidence to shallow layers, the vertical drain functions as a loading box.

して小さくなっていく。また、圧密増加荷重による沈下の大きさは、土被り圧

に大きくなるので対数値は深さ方向に小さくなる。深い層は沈下の寄与の割合が小さい。従って、航路・泊地の水深の確保は、深い層を外して浅い層に限定する。これにより、バーチィカルドレーンは短いものでよい。真空圧密工法は載荷面を気密にする必要がある。このため、海底地盤の載荷板は載荷函体の構造となって気密機能を担っている。バーチィカルドレーンの長さは載荷函体の外周壁の高さで十分である。載荷函体内部に必要な間隔で格子状に隔壁を設けて外周壁の内面及び隔壁の両面にドレーン機能を持たせる。How to secure the water depth of the route / night anchorage, how much more subsidence in a short time (limited time)

And get smaller. The size of settlement due to increased consolidation load is

Therefore, the logarithmic value becomes smaller in the depth direction. The deep layer has a small contribution to the settlement. Therefore, securing the water depth of the channel and anchorage is limited to the shallow layer by removing the deep layer. Thereby, the vertical drain may be short. The vacuum consolidation method needs to make the loading surface airtight. For this reason, the loading board of the submarine ground becomes the structure of the loading box and has an airtight function. The length of the vertical drain is sufficient at the height of the outer peripheral wall of the loading box. A partition wall is provided in a lattice shape at a necessary interval inside the loading box, and a drain function is provided on the inner surface of the outer peripheral wall and both surfaces of the partition wall.

Keep the bottom soil that has been dewatered and reduced in volume to the required strength, and cut, transport, and reuse it. For this problem, a bottom plate is installed in which the bottom surface of the loading box opens and closes horizontally. And it is the strength maintenance of submarine soil when the bottom is closed.
A shutter for a bottom plate (an armor door) is vertically stored on an outer peripheral wall partitioned by a partition wall and a unidirectional surface of the partition wall. When the shutter is opened and closed as the bottom of the loading box, the shutter is horizontally changed in the vicinity of the tops of the blade edges of both walls, and is horizontally put in and out of the bottom of the loading box. As a support for the bottom plate, a part of the outer edge of the outer peripheral wall and partition edge parallel to the direction in which the shutter is put in and out is used as a vertically supported movable support. The image moves horizontally through the compressed seabed soil inside the loading box as if the bottom plate gently cuts the hard sheep, closing the bottom.

  Next is strength maintenance during transportation of submarine soil. The loading box with the seabed soil still clogged is raised and stopped and fixed at a predetermined position below the surface of the work boat. In the case of the construction method of Patent Document 1, it is directly under the trolley, but the present invention is in a position parallel to the trolley. This is intended for transport and to reduce drafts. The reason why the position is below the water surface is to reduce the burden on the bottom plate by leaving the buoyancy of the seabed sediment inside the loading box.

Next is strength maintenance when seabed soil is reused. Here, it is assumed that the seaweed beds are reused. In the embankment, the loading box is lowered and grounded to the seabed ground, pressure is sent to the loading box to press down on the inner seabed soil, and the loading box is raised to extract and fill the seabed soil.
The above is a loading box that reduces the volume of dehydrated seabed soil, raises it to a predetermined strength, and performs a series of operations such as cutting, transporting, and embankment. Cutting and embankment of seabed soil, characterized in that the seabed soil is always packed in a loading box, the strength is maintained by suppressing contact between the seabed soil and seawater, and the occurrence of seawater contamination is suppressed. It is the outline of the system construction method.

Efficient construction method for dredging in large-scale dredging works. This problem is solved from the capabilities of the work boat.
The capacity of a work boat corresponding to the scale of dredging is based on the size of the loading box, that is, the size of the loading area. For large dredging, it is necessary to increase the capacity of the work boat. One solution is to increase the loading area. The mechanism of the work ship is a plurality of arrays of loading boxes.

  Now, it is assumed that a work ship having a work capacity of n times is prepared. The loading area becomes n times, and each function requires a device with n times the capacity. Here, if the ready-made apparatus used is the largest, it is usually solved by connecting a plurality of apparatuses. However, the loading function here is loading of both a static static load (atmospheric pressure + water pressure) and a repeated load. Multiple loading devices cannot be connected. In other words, it is necessary to match the phases of the eccentric motors of a plurality of repetitive loading apparatuses, but this is not possible. Therefore, n sets of loading devices and loading boxes are prepared.

  An efficient construction method regardless of the size of the dredged soil control method. This problem is solved from the work speed and work accuracy. The means is a traveling spud on the outer periphery of the work boat.

  As a work ship equipped with a spud that can reciprocate on the work ship in the hull axis direction, there is a work ship disclosed in Patent Document 2. This self-moving function of the work ship is suitable for the work movement of a conventional dredger. For example, the working trajectory of a conventional dredger becomes an area by moving a line. That is, it is only necessary to repeat the short movement according to the work speed. The work trajectory of the work boat of the present invention is an area from the beginning. It is also a scale with a width of 25 m and a length of 50 to 100 m. The work ship according to the present invention must have a function of corresponding hull movement.

The spud device moored by the work ship is fixed to the outside of the ship on four three-dimensional carts with four wheels that run on the track (two rails) provided on the outer periphery of the work ship. In order to prevent this toppling, a horizontal support movable support is adopted for the horizontal members of the connecting members of the three-dimensional frameworks of a plurality of carriages, thereby forming a spud that can be stably and quickly driven. When this mobile spud travels in the ground support pile state, the work ship moves, and in the released state of the ground support pile, the mobile spud moves.
The mobile spud according to the present invention is specialized for self-moving work vessels. The track of the bogie that runs on the outer periphery of the work ship cannot be taken widely. For this reason, in order to prevent a three-dimensional cart with a large eccentricity from falling, the track is narrowed and miniaturized by taking a reaction force on the three-dimensional framework of the cart. In addition, each three-dimensional trolley is equipped with a generator and is driven by a motor.

In the mechanism of the work ship and the loading box, the loading box is a huge spud fixed to the work ship.
Offshore operations are susceptible to tidal currents and waves. However, the work vessel has a tower-type loading box that acts as a huge spud, reducing the effect. The work ship is also equipped with a spud, but the purpose is to move the work ship accurately and freely.

The vertical drain functions as a loading box.
The construction method of Patent Document 1 is preceded by a work ship for placing a vertical drain on the seabed and a sand mat, followed by a ground consolidation ship with rapid consolidation. This preceding construction is deleted. The effect is a reduction in construction costs for the preceding construction. The work time does not significantly reduce the work time because the preceding work and the improvement work become parallel work. However, the number of ships on the main route is very large, and the reduction of processes by the preceding work vessels is a great advantage from the viewpoint of navigation safety.

As a means of cutting undersea soil, a bottom plate that opens and closes horizontally is installed in the loading box.
The construction method of Patent Document 1 already had a function of reducing dehydration and volume for all the seabed ground. However, since there is no means for carrying out the reuse, it is not possible to carry out a minimum amount of submarine soil, and the applicable ground is limited. The fundamental change is the bottom plate that opens and closes the bottom of the loading box horizontally.
The inflow sediment in the channel and anchorage has a large gap and is highly compressible. However, since the sediment thickness does not become zero even when loaded with a large load, the shortage is calculated in the subsidence of the conventional submarine ground. Since the water depth maintenance management of the route and anchorage continues constantly, the subsidence of the conventional ground will reach its limit as it is repeated many times. Even in the case of high plastic clay ground, it will be forced to carry out seabed soil in the future.

Next, as for the means of transporting the submarine soil, the position of the loading box is parallel to the carriage and below the water surface. The effect of this is to reduce the load on the bottom plate by suppressing the draft and suppressing the resistance of water during operation and leaving the buoyancy of the seabed sediment inside the loading box. Incidentally, the saturated unit volume weight of the compressed submarine clay is about 16.0 kN / m ³ and the unit volume weight of water is 9.81 kN / m ³ , so the unit volume weight in water is 6.19 kN / m ^3. Is about 60% weight reduction.

Next, the means for reusing the seabed soil (filling) is a pressurizing function of the loading tower and loading box that reach the bottom of the sea. The embankment work of the system construction method of the present invention does not cause the seabed soil to fall into the sea. Hold the seabed soil raised to the required strength as it is and fill it directly on the seabed.
The effect as earth work has a strength as a banking material, so a predetermined banking gradient is ensured. If necessary, slope protection work can be performed later. Since the conventional dredged soil exceeds the liquid limit, the embankment gradient cannot be formed. Therefore, submerged dike construction is required in advance.
The environmental effect is to prevent seawater pollution. Seaweeds need light energy for their survival. As the water depth increases, the amount of light transmitted decreases. In particular, when the transparency decreases, the amount of light decreases drastically. Seawater pollution and floating mud generation will cause existing natural algae beds to decline. There is no point in degrading existing seaweed beds by creating a seaweed bed.

The effect of both earthwork and the environment is that construction can be performed without change unless the water depth is extremely deep.
Seaweeds have a depth of water and a guaranteed depth that provides the minimum amount of light necessary for their survival. Depending on the transparency of the water, it is usually said to be a few to a dozen meters in the inner bay. Such a shallow field is often a target for landfilling, which causes a significant decrease in algae fields. Here, we plan to create a seaweed bed for the seabed at a depth exceeding the guaranteed depth. If an artificial algae basin is built on a natural good algae basin, it may eventually become a simple dumping ground.

A work ship equipped with multiple loading boxes.
The effect of this is that the arrangement of a plurality of loading boxes can easily prepare a work ship having the capacity corresponding to the construction scale. In addition, the array of multiple tower-type loading boxes is an array of huge spuds, making it a work ship that is resistant to marine weather conditions. In addition, the arrangement of a plurality of loading boxes enables various variations as a system construction method using the running function of the spud. For example, there is a two-stage loading of a loading box.

A work ship equipped with a spud with a traveling function on the outer periphery of the work ship.
The work ship can translate itself back and forth and left and right. The travel distance is the total length and width of the work boat. Moreover, accurate rotation is possible by using one spud as a support pile for the seabed and operating the remaining three. These effects are due to the fact that the boundary between the completion and incomplete compression of the submarine ground is clear from the mutual relationship between the outer peripheral position of the work ship and the outer peripheral position of the loading box, and it is possible to move quickly and accurately to the next predetermined work position. is there. In addition, since the boundary can be moved accurately, it is easy to adjust the height of the submarine ground by cutting and embankment in the work area and to perform the two-stage loading system method.
Dredging work is a repetitive work in which the work boat sequentially moves the work position. Therefore, the moving speed and moving accuracy are important, and the construction period and cost are greatly affected by the construction efficiency. Long movements (50m to 100m) are usually moved using an attached ship such as a push boat, but the work ship is not required. In addition, the movement of work vessels by pushing boats is not accurate.

  FIG. 1 is a side view showing an embodiment of the work boat according to the present invention, and FIG. 2 is a plan view thereof. The construction of the work ship 1 is a base ship 2, a base ship combined solid frame 3 for three-dimensionally connecting it, a guide tower 4 integrally formed with the solid frame 3, a tower type loading box 5 and a work ship incorporated therein. It consists of a movable spud 6 as one moving means. The work boat 1 shown in FIGS. 1 and 2 is an example in which four carriages 2 and two loading boxes 5 are configured. Further, two rail tracks 7 and one movable spud 6 are arranged on each of the four sides of the outer periphery of the work boat 1. However, the three-dimensional frame 3 is omitted from the plan view of FIG. In the figure, 12 is the sea level, and 13 is the seabed ground.

  FIG. 3 is a side view of the work ship, but FIG. 3A is a side view of the work ship with the tower-type loading box 5 separated. FIG. 3B is a single side view of the tower type loading box 5. The structure of the loading box 5 is provided with an automatic valve 5b for controlling the flow of water in and out of the rigid loading plate 5a, and a loading tower 5c having a height reaching the sea bottom is attached to the center of the upper surface of the rigid loading plate 5a. The space 5d (drain layer) and the rigid filter 5e are provided in two stages, the outer peripheral wall 5f is joined to the outer periphery of the bottom surface, and the partition wall 5g having a drain function in a lattice form below the bottom surface of the rigid loading plate 5a. It is a tower type loading box 5 in which The loading tower 5c is equipped with a repeated loading device 8. Further, as ancillary equipment, there are a vacuum pump 9 and a compressor 10. The self-propelled spud 6 includes a spud 6a, a three-dimensional cart 6b, and a horizontally supported movable support 6c.

FIG. 4 is a side view of the loading box 5 pushed into the seabed ground. At this time, the inside of the loading box 5 is in an airtight state.
An example of the shape and dimensions of the loading box 5 is as follows. The rigid loading plate 5a is a square of 24 m × 24 m, and the thickness is 0.5 m including the minute space 5d and the rigid filter 5e. The height of the outer peripheral wall 5f is 3.5 m, and the height of the partition wall 5g is 3.0 m. One interval of the partition walls is 4.0 m, and the other interval is 1.0 m. The horizontal drainage distance of the submarine soil clogged inside the loading box 5 is 0.5 m.

The system construction method of the present invention in the submarine soil construction (dredge construction) for securing the water depth of the route / night is explained in order.
The work ship 1 is towed to a predetermined position in a cut work area (construction area) for maintaining the water depth. The positional relationship of the loading box 5 is as shown in FIG. 1 immediately below the water surface. Next, the loading box 5 is pushed into the seabed ground. It is the state of FIG. By depressurizing the inside of the loading box 5, an applied load of atmospheric pressure and water pressure is applied, and the inflow sedimentary soil and the conventional seabed soil are simultaneously compressed. When the subsidence reaches a predetermined dredging depth, pressurized air is sent to the loading box 5 to hold down the seabed soil inside, and the loading box 5 is raised to leave the bottom soil. The operation at this position is completed only by compression settlement. There is no unloading of seabed soil.

  If the subsidence does not reach the prescribed depth, the lack of subsidence will be compensated by carrying out the seabed soil. However, the submarine soil transported at this time is recycled soil (material) whose strength is increased and volume is reduced. The unloading of the seabed soil is cut and transported to the receiving work area.

Cutting is performed by closing the bottom plate shutter 11a of the loading box 5 horizontally. 5 and 6 are vertical sectional views of the loading box 5. However, it is a vertical cross-sectional view in which both sides of the loading tower 5c and the loading box 5 are omitted with the central portion omitted.
A bottom plate shutter 11a is vertically accommodated in the outer peripheral wall 5f and the partition wall 5g of the loading box 5. One of the intervals of the grid-like partition walls 5g is 4.0 m and the other is 1.0 m. The bottom plate shutter 11a is housed on the vertical walls of the outer peripheral wall 5f and the partition wall 5g that are perpendicular to the partition walls 5g at intervals of 4 m. FIG. 5 is a view in which the partition wall 5g with a 1 m interval is directed to the front, and the bottom plate shutter 11a is vertically housed on the back surface thereof. The size of the shutter 11a is approximately 1. m width is 4 m. In FIG. 6, the partition walls 5 g with a distance of 4 m are directed to the front, and the partition walls 5 g with a distance of 1 m are shown as a vertical cross section.

  FIG. 7 is an elevation view for explaining the bottom opening / closing system device 11 of the loading box 5. This system unit 11 is composed of a plurality of shutters 11a, two drive units 11b (double-acting hydraulic cylinders) that move the shutters, cords 11c (chains, wire ropes, etc.) that connect them, and two types that change the direction. The fixed pulley 11d. This system is completed inside the loading box 5 which can be kept airtight.

FIG. 7A shows a state in which the shutter 11a is stored and the bottom surface of the loading box 5 is opened. The bottom opening / closing system device 11 is connected by a cord-like object 11 c and goes around the inside of the loading box 5.
The bottom opening / closing system device 11 starts from one drive device 11b inside the outer peripheral wall 5f, changes its direction horizontally by the fixed pulley 11da, passes through the inner upper surface of the loading box 5, and is moved by the fixed pulley 11da on the opposite outer peripheral wall 5f. The direction is changed downward and connected to the shutter 11a. The direction is changed again horizontally by the fixed pulley 11db at the bottom of the outer peripheral wall 5f and passes through the inner bottom surface of the loading box 5, and the original pulley 11db of the original outer peripheral wall 5f is used. It is connected to the other driving device 11b whose direction is changed by changing the direction upward. The installation of the two drive devices 11b is due to the fact that the cords 11c can only transmit tension.
A shutter 11a is also stored in each partition wall 5g. It is necessary to interlock these with the cord-like object 11 c that goes around the inside of the loading box 5. The two fixed pulleys 11da and 11db of each partition wall 5g are connected by a cord-like object 11c. Here, the fixed pulley 11d at the bottom of the loading box 5 is a long fixed pulley 11db because the shutter 11a passes therethrough.

FIG. 7 b shows a state where the shutter 11 a is pulled out and the bottom surface of the loading box 5 is closed.
The difference between FIG. 7a and FIG. 7b is the position of the shutter 11a by opening and closing the bottom surface of the loading box 5, the state of the two driving devices 11b in conjunction with this, and the cords 11c connecting the shutters 11a of the respective partition walls 5g. This is a deviation.

  FIG. 8 is a side view of the lower portion of the outer peripheral wall 5f and the blade edge 5fa thereof. The outer peripheral wall 5f of FIG. 8a houses the shutter 11a, and FIG. 8c is provided with the driving device 11b. The outer peripheral wall 5f in FIG. 8b is a wall that goes directly to the walls in FIGS. 8 and 9, and a part of the top edge of the blade edge 5fa serves as a movable support for vertically supporting both ends of the bottom plate shutter 11a.

  FIG. 9 is a side view of the lower part of the partition wall 5g and the blade edge 5ga thereof. In the partition wall 5g of FIG. 9a, the shutter 11a is accommodated, and the shutter 11a passes through the lower end thereof. The partition wall 5g in FIG. 9b is a wall that goes directly to the wall in FIG. 9a, and a part of the top edge of the blade edge 5ga serves as a movable support that vertically supports both ends of the shutter 11a for the bottom plate.

  FIG. 10 is a side view showing a state in which the inside of the loading box 5 is depressurized, and the seabed soil is compressed and sunk by a loading load of atmospheric pressure / water pressure to a predetermined strength. If the subsidence does not reach the predetermined dredging depth, the submarine soil that is insufficient for subsidence is carried out (cut or transported). Cutting is performed by closing the bottom plate shutter 11a of the loading box 5 horizontally.

  Next, the airtight state of the loading box 5 is released, the atmospheric pressure and the water pressure are unloaded, the loading box 5 in which the seabed soil is filled is lifted, and stopped at a predetermined position below the surface of the work boat 1. To do. The position of the loading box 5 is in the state shown in FIG. Seabed soil is transported underwater.

  Next, in the embankment work zone, the loading box 5 is lowered to the seabed ground. FIG. 11 is a side view of the descending grounding state. Next, the bottom surface of the loading box 5 is opened, the seabed soil in an intermediate state is pressurized, and the loading box 5 is raised to extract the seabed soil and fill it.

  The unloading of the seabed soil is used by filling up the capacity of the loading box 5 in view of construction efficiency. When all the packed submarine soil in the loading box 5 is taken out, it becomes deep. In this case, the seabed soil is carried out in the form of a belt and the depth is adjusted by cutting. FIG. 12 is a side view for explaining the height adjustment by cutting in the ridge area. In the figure, the AA line is the current seabed height, the BB line is the dredged ground height, and the CC line is the compression sinking ground height.

  If subsidence does not reach the predetermined dredging depth, but the destination of the seabed soil is not convenient, a predetermined dredging depth is secured by two-stage loading. FIG. 13 is an explanatory diagram of a two-stage loading system using two loading boxes 5. The line height in the figure is the same as in FIG.

  FIG. 13a shows that the current sea level of the AA line is already the height of the compression sedimentation base of the CC line, but has not reached the height of the basement of the BB line. Therefore, the preceding loading box 5 is in a state in which the submarine soil is lifted and moved laterally in the middle packing state.

FIG. 13 b shows a state in which the subsequent loading box 5 is pushed into the cut ground of the preceding loading box 5. This state is in the position of the water depth in which the compression settlement of the CC line and the cutting depth of the preceding loading box 5 are added. When the amount of settlement is 1 m and the height of the partition wall 5 g is 3.0 m, the compression increase load due to water pressure is about 40 kN / m ² . This is the meaning of the two-stage loading.

FIG. 13 c shows a state in which the subsequent loading box 5 obtains a compression increasing load and further compresses and sinks. Then, the seabed soil inside the box is left and backfilled with the middle packed seabed soil of the preceding loading box 5. There is no problem even if the vertical cut part collapses a little. When the preceding loading box 5 is backfilled with the seabed soil, it is compressed and shaped again. This is because the work boat 1 of the present invention can move accurately. This suppresses the removal of submarine soil.
As described above, in a series of operations from increasing the strength of the seabed soil to cutting, transporting and embankment, the seafloor soil is always packed in the loading box to maintain the strength and suppress the occurrence of seawater pollution. This is an outline of the system construction method for cutting and embankment of the characteristic submarine ground.

  It is a side view which shows one Example by the working ship 1 of this invention.   2 is a plan view of the work boat 1 similarly. FIG.   It is a side view of the work ship 1 which separated the loading box 5.   It is a side view of the state which pushed the loading box 5 of the work ship 1 into the seabed ground.   FIG. 4 is an enlarged side view of one side of the loading box 5.   It is the other enlarged side view of the loading box 5 similarly.   FIG. 3 is an elevation view for explaining the bottom opening / closing system device 11 of the loading box 5.   It is a side view of the lower part of outer peripheral wall 5f, and blade edge | tip 5fa.   It is a side view of the lower part of the partition 5g, and the blade edge | tip 5ga.   FIG. 3 is a side view of a state in which seabed soil is compressed and subsidized by the loading box 5 of the work ship 1.   Side view of the state where the submarine soil transported by the loading box 5 descends to the embankment submarine ground.   It is a side view for description of height adjustment by the cut in the ridge area.   It is a side view for description of a two-stage loading system using two loading boxes 5.

DESCRIPTION OF SYMBOLS 1 Work ship 2 Cargo 3 Cargo combined solid frame 4 Guide tower 5 Tower-type loading box 5a Rigid loading board, 5b Automatic valve which controls entry / exit of water, 5c Loading tower 5d Minute space, 5e Rigid filter, 5f Peripheral wall, 5g Bulkhead 6 Mobile spud 6a Spud, 6b Three-dimensional frame cart, 6c Horizontal support movable support 11 Bottom opening / closing system device 11a Shutter, 11b Drive device (double acting hydraulic cylinder),
11c Cords (chains, wire ropes, etc.), 11d Regular pulley 12 Sea surface 13 Submarine ground surface

Claims (5)

  In cutting and embankment work on the submarine ground, a work that is equipped with a tower-type loading box with a loading tower that reaches the bottom of the sea at the center of the upper surface of the rigid loading board and an outer peripheral wall joined to the outer periphery of the bottom By using a ship, in the cut area where the water depth is maintained, the loading box is pushed into the submarine ground and the inside of the loading box is depressurized in an airtight state. When the volume of the seabed soil is reduced and increased to the specified strength, the load is unloaded and the bottom surface of the loading box is closed, and the loading box with the seabed soil filled is raised to Stop at a predetermined position below the surface of the water, and transport the submarine soil underwater with a loading box.In the embankment construction area, lower the loading box to the bottom of the seabed, pressurize the padded seabed soil and remove the loading box. Raise the seabed soil and raise and fill it, so the seabed soil is always loaded As Wadding state, volume reduction and strength of the compression subsidence marine soil of the ground without generating seawater contamination increases, the system construction method Cut-embankment Seabed which is characterized in that to fill reuse.   The loading box used in the system method for cutting and embankment according to claim 1, wherein partition walls are provided in a lattice shape in the inner space of the loading box, and a drain function is provided inside the outer peripheral wall and on both sides of the partition wall. A tower-shaped loading box.   In the work ship according to claim 1, the main structure of the work ship is composed of a plurality of carriages and guide towers that are floating bodies, and a tower-type loading box according to claim 1, wherein the plurality of carriages are one of the loading boxes. Submarine ground that has multiple loading boxes by connecting three or more guide towers to the frame of the connecting material and incorporating a tower type loading box in each guide tower. A work boat used in the system construction method for cutting and embankment.   3. The loading box according to claim 2, wherein the shutter for the bottom plate is vertically stored on the outer peripheral wall partitioned by the partition wall and one direction surface of the partition wall, and the shutter is opened and closed as the bottom surface of the loading box by the shutter. Change the direction horizontally near the top of the blade edge and place it horizontally in and out of the bottom surface of the loading box. The bottom plate is supported by a part of the top edge of the outer peripheral wall and partition wall parallel to the shutter loading and unloading direction. A tower-type loading box that has a function to open and close the bottom of the loading box with both ends supported vertically.   4. The work ship according to claim 3, wherein four-wheeled trucks having four wheels self-propelled on a track provided with a spud device moored by the work ship on four outer sides of the work ship are directed to the outside of the ship. It is fixed, and the fall of this is taken by a horizontal support movable support on the horizontal member of the three-dimensional framework of the carriage, and when the spud runs in the ground support pile state, the work ship moves and the ground support pile is released. A work ship equipped with a mobile spud characterized by the fact that the work ship can move precisely and quickly through the full length and front width of the work ship as the spud moves in the state.

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